DEAR ABBY: I work in a small sales office. We are all women, and despite the potential for intense competition (we work on commission), everyone pretty much gets along.

One woman, however, is constantly challenging, questioning and putting me down personally and professionally. She ridicules my opinions in planning meetings, implies I'm making things up in all sorts of situations, and argues with everything I do and say, even if it is not her business. She spends large amounts of time on personal phone calls, which interrupt my concentration, and mocks me for not doing the same.

My manager, while sympathetic, tells me I'm a far more experienced "pro" and to ignore her. It's nice that management recognizes my experience and commitment, but I'm increasingly frustrated and angry with my co-worker. Her aggravating behavior needs to stop. Any efforts I've made to make her understand have been met with defensiveness or just plain name-calling (in a laughing way).

How do I put a stop to her behavior while continuing to be a team player? I'm ready to look for another job, but I love this one -- except for her. -- STYMIED IN SAN DIEGO

DEAR STYMIED: Name-calling, implying you are making things up and ridicule are not acceptable office behavior. Make notes of the date and time of each abusive incident. Then ask the office manager to insist on mutual respect in the work place. It is your employer's responsibility to provide a nonhostile working environment.

DEAR ABBY: If you have room for one more letter about "Disillusioned in Dallas," the gentleman whose manners were unappreciated, feel free to print mine. I am female, and I, too, live in Dallas -- and I'm wondering if this is indigenous to the women of our city.

I am happily married to a mannerly gentleman (one of the many traits that make him so desirable), and we have recently begun teaching our young son the social graces. He practices holding doors open for women while we're out shopping. He smiles as he props his 4-year-old body against the door to hold it open, and incredible as it sounds, not one woman under the age of 50 has ever thanked him.

When this occurs, I forgo my manners and say to my son (loudly enough for the offender to hear), "She should've thanked you, but her manners aren't as good as yours." I would have to say the same applies to "Disillusioned's" acquaintances.

If these rude, self-absorbed women aren't appreciative of, or touched by, the efforts of a young boy, it's no surprise that they're equally unappreciative of such courtesies extended by the gentleman they choose to date.

Abby, please tell "Disillusioned" to continue his courteous, respectful manners, and I will continue teaching them to my son. The women of Dallas have a legacy of being some of the most beautiful, successful women in the country. I'm hopeful that in the future, they'll also be known for their good manners. -- DETERMINED IN DALLAS

DEAR DETERMINED: Anyone who would ignore the efforts of a child to do the right thing must have a heart of stone. A stranger pausing to praise a child for being well-behaved or practicing good manners can leave an even more lasting impression than when a parent does it.

Stick to your guns, Mom, and continue to teach your son the social graces. They're still something that well-bred people need to know.

What teens need to know about sex, drugs, AIDS, and getting along with peers and parents is in "What Every Teen Should Know." To order, send a business-sized, self-addressed envelope, plus check or money order for $3.95 ($4.50 in Canada) to: Dear Abby, Teen Booklet, P.O. Box 447, Mount Morris, IL 61054-0447. (Postage is included.)